Breaking New Ground:

A World First from Evonik Degussa: Modular Sol-Gel System for Coating Metals

Whenever conventional coating systems containing standard organic binders reach the limits of their capabilities, sol-gel systems are used. Up to now, these have had the disadvantage of being technically difficult to handle. But things are about to change, thanks to the specialists of Evonik Degussa's Aerosil & Silanes Business Unit. The modular system consists of various water-based sol-gel components comprising a water-based binder and other water-based additives. For the first time ever, formulators and developers of coating systems are being offered a simple method for producing sol-gel coatings with specific properties and good storage stability— thanks to Evonik Degussa's new SIVO^® SOL technology. Both hard and flexible SIVO^® SOL technology is a novel, modularly organized, water-based sol-gel system that is particularly suitable for metal pretreatment and metal coating applications. The additives have been specially designed for compatibility with the new sol-gel binder Dynasylan^® SIVO 110. The modular concept allows an unusually high degree of flexibility in the formulation of water-based scratch- and abrasion-resistant sol-gel coatings, which can also be given anticorrosive or easy-to-clean properties if required. In addition to Dynasylan^® SIVO 110, the new sol-gel system consists of three additives: the neutralizing agent SIVO 111, the anti-fingerprint and oleophobizing additive SIVO 112, and the hydrophobizing additive SIVO 113 for improved weathering stability.

The main applications center on metal coatings as used in metal pretreatment, corrosion-protection primers, and anti-fingerprint finishes. The additives are mixed into the base component in various concentrations, depending on the field of application, to achieve the required properties in the coating. The coating films obtained are hard and resistant to abrasion as well as to chemicals and solvents, yet possess surprising flexibility. SIVO^® SOL technology is particularly suitable for aluminum, steel, galvanized steel, and other pretreated metal surfaces.

The system is usually applied to the substrate by spraying or dipping. It significantly improves the corrosion properties of metal surfaces. Other possible applications SIVO^® SOL technology can be used for topcoats on metals, glass, and ceramic materials. It is also suitable for the manufacture of easy-to-clean and anti-graffiti surfaces. Inorganic silane-based coatings are significantly harder than traditional organic binders. They also react chemically with the metal surface and have the ability to improve adhesion of further coating films. Acting as barriers to water and salts, they inhibit corrosion and generally show outstanding weathering resistance. However, systems of this type have so far suffered from the disadvantage that the coatings could be obtained only via high-solvent formulations. With the new Dynasylan^® SIVO class of products, Evonik Degussa has overcome this traditional drawback. SIVO^® SOL technology is a water-based modular system for the formulation of inorganic sol-gel coating materials that are virtually solvent-free and are stable in storage.